Characterization of novel aluminium powders for the development of components using the powder metallurgy process.

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Aluminium components produced by the Powder Metallurgy process generally require additions of magnesium to promote liquid-phase singeing. Indeed, melting of magnesium during sintering mechanically disrupt the oxide layer found at the surface of Al particles while acting as a scavenger for residual oxygen molecules found in the surrounding sintering atmosphere. This strategy promotes the formation of numerous metal-metal points of contact that act as nucleation sites for the formation and growth of sintered necks. Although this approach yields components with good mechanical properties, parts produced by this route sustain significant distortion, which typically requires secondary shaping operations to give them their desired shape. ****Equispheres Inc. has developed a unique process for manufacturing spherical metal powders. The latter are renowned for having a significantly thinner oxide layer than powders of identical alloys produced by inert gas atomization. Therefore, it is postulated that this thin oxide layer could be mechanically disrupted during the compaction stage of the PM process, therefore requiring much less magnesium, if any, during sintering. The final outcome would be the production of PM Al components that would require minimal secondary shaping operation and possibly none a tall.****The work carried out in this project will seek to maximize the compressibility of Al powders by developing synthetic particle size distributions. Additionally, optimization will be done to determine the ideal thermal profile for sintering as a function of green density and magnesium content. Finally, the effect of the latter parameters on specimen distortion and tensile mechanical properties will be quantified.****